This invention relates to the field of organic chemistry, and more particularly to novel triiodobenzoic acid derivatives useful as X-ray contrast agents.
Many 2,4,6-triiodobenzoic acid derivatives have been proposed for use as X-ray contrast agents. These include, among others as a subgroup, many 2,4,6-triiodoisophthalamic acid derivatives. Among the latter, certain N-hydroxyalkyl-2,4,6-triiodoisophthalamic acids have been disclosed. For example, both Guerbet et al. U.S. Pat. No. 3,622,616 and Salvesen et al. U.S. Pat. No. 3,702,866 disclose 5-acetamido-N-(2-hydroxyethyl)-2,4,6-triiodoisophthalamic acid. In addition, Salvesen et al. also disclose the compound N-(3-acetamido-5-carboxy-2,4,6-triiodobenzoyl)-N-methylglucamine, which may also be designated 5-acetamido-N-(D-gluco-1-deoxy-2,3,4,5,6-penta-hydroxyhexyl)-2,4,6-triiodo -N-methylisophthalamic acid.
Further, Almen et al. (U.S. Pat. No. 3,701,771) disclose a considerable number of non-ionic N-(2,4,6-triiodobenzoyl)-amines said to be useful as X-ray contrast agents in the cerebrospinal cavities, including one (compound 41) derived from tris(hydroxymethyl) aminomethane. This compound is designated as N-[3-N-methylacetamido-5-N-(beta-hydroxyethyl)-acetamido-2,4,6-triiodobenz oyl]N-[tris(hydroxymethyl)-methyl] amine. This compound was reported to have a rather low water solubility (0.86%) although many other compounds in the series were disclosed to be relatively highly soluble in water.
The use, as X-ray contrast media, of aqueous solutions of salts of various 2,4,6-triiodoisophthalamic and other 2,4,6-triiodobenzoic acids with pharmaceutically acceptable cations such as sodium, calcium and magnesium and alkanolamines such as ethanolamine, diethanolamine and meglumine (N-methylglucamine), is well known to those skilled in the art.